A pull-on absorbent article is known, which includes an hourglass-shaped outer cover having a front portion, a crotch portion, and a rear portion adapted to be applied to the front side, crotch, and rear side, respectively, of a wearer and an absorbent assembly fixed to the inner side of the outer cover, with both the lateral side edges of the outer cover in the front portion and those in the rear portion being joined together to form a waist opening and a pair of leg openings.
Continuous production of such pull-on absorbent articles generally includes the steps of making through-holes or cutouts in a continuous length of outer cover to form leg openings (trimming step) and removing the unnecessary parts (trimmings).
Conventional pull-on absorbent articles include those in which the outer cover is separated into a front side outer cover to be worn around the front side of a wearer and a rear side outer cover to be worn around the rear side of the wearer, and the absorbent assembly is fixed to bridge the front side outer cover and the rear side outer cover, with both lateral side edges of the front side outer cover and those of the rear side outer cover being joined together so that the front and the rear side outer cover are connected to make a loop. An example of this type of pull-on absorbent articles is the disposable pull-on garment disclosed in patent literature 1 (see below), which has a ring-like elastic belt composed of a front belt portion and a back belt portion and an absorbent main body, the back belt portion (i.e., rear side outer cover) having a larger length in the longitudinal direction than the front belt portion (i.e., front side outer cover) in the longitudinal direction.
Another example is the disposable pull-on diaper disclosed in patent literature 2 (see below), which includes a cylindrical below-waist portion foamed of a front outer cover sheet and a rear outer cover sheet and an absorbent assembly, wherein the rear outer cover sheet includes a main portion and a rear extension portion extending downward from the main portion. The rear extension portion includes a buttock covering subportion on both sides thereof, and second elastic members disposed in the buttock covering subportions have a higher stretch ratio than the first elastic members disposed in the middle part and the lower end part of the main portion of the rear outer cover.
Patent literature 3 (see below) describes a garment, which is not of the type having an outer cover separated into a front outer cover and a rear outer cover, having auxiliary elastic members between an outer and an inner sheet of the outer cover, wherein the auxiliary elastic member has both ends thereof secured to the outer and inner sheets at opposite sides of the below-waist portion of the garment, with a middle portion between the two ends being not secured to either the outer sheet or the inner sheet.
Patent literature 4 (see below) describes a disposable diaper, which is not of the type having an outer cover separated into a front outer cover and a rear outer cover, in which elastic members disposed between sheets of an exterior laminate (outer cover) are cut in a region overlapping the front portion of the absorbent assembly to provide a non-elasticized region, the non-elasticized region having a gradually increasing width from its end closer to the waist opening edge of the front portion to the middle thereof and a uniform width from the middle to the opposite end closer to the longitudinal center of the diaper.
The assignee common to this application previously proposed absorbent articles, like a disposable diaper, including an absorbent assembly and an outer cover, in which the outer cover has a specifically configured composite stretch panel forming a below-waist gather in the below-waist portion thereof (see patent literatures 5 and 6 below). The composite stretch panel used in these absorbent articles is composed of an outer sheet and an inner sheet bonded to each other at bonds discretely arranged in the stretch direction and a direction perpendicular to the stretch direction. Elastic members are disposed at positions other than the bonds and not fixed to either the outer sheet or the inner sheet at other than their opposite ends so that each of the outer sheet and the inner sheet may form a plurality of folds continuously extending across a plurality of the elastic members.
Patent literature 7 below discloses a pull-on article having an outer cover composed of two sheets discretely bonded to each other at bonds formed by embossing and elastic members passing between the bonds. Separately from the bonds formed by embossing, the outer cover has fixing points arranged along the curving edge forming each leg opening where one end each of elastic members is fixed.